The present invention relates to a bipolar high frequency treatment tool that is to be inserted into a human body through an accessory channel of an endoscope.
A typical bipolar high frequency treatment tool is disclosed, for example, in Japanese Patent Application Provisional Publication No. P2000-271128. The treatment tool disclosed in the above-mentioned publication has a pair of electrodes mounted to a distal end of a flexible sheath so as to open and close like a pair of pincers.
The pair of electrodes is coupled to a pair of wires to be remotely operated, or opened and closed, from the proximal end of the treatment tool by advancing/retracting the wires within the sheath. The wires are also utilized to supply high frequency power to the electrodes. That is, the wires are arranged to connect one of the electrodes with a positive pole of a high frequency power supply while the other one with a negative pole.
In order to prevent short circuits between the wires placed side by side in the sheath, the wires are covered with insulating layers or covers. The insulating layers of the wires, however, cannot be made thick since the overall diameter of the wire is restricted to a small amount due to the small inner diameter of the sheath. Thus, sufficient insulation between wires could not be achieved when a large amount of high frequency voltage is applied between the wires.
Therefore, there is a need for a bipolar high frequency treatment tool for an endoscope in which wires supplying high frequency power to an end effector is sufficiently insulated from each other.